An April 15, 2012 photo of a North Korean vehicle carrying a missile during a mass military parade in Pyongyang's Kim Il Sung Square to celebrate the centenary of the birth of the late North Korean founder Kim Il Sung.

Western experts say a vehicle carrying a missile that was recently glimpsed in a North Korean military parade looks to be designed by China, raising the possibility that North Korea's closest ally is violating U.N. sanctions on Pyongyang.

Defense analysts from the publication Jane's Defence Weekly have told reporters this week that North Korea's 16-wheel vehicle, known as a transporter-erector-launcher, bears many similarities in detail to its Chinese counterparts. That raises the possibility that the vehicle could have been manufactured or designed in China.

The U.N. Security Council Resolution 1874, passed three years ago after North Korea conducted its second nuclear test, prohibits supplying Pyongyang's weapons program with arms, money, training, or other assistance.

China has denied any wrongdoing in connection with the vehicle. Foreign Ministry spokesman Liu Weimin said Thursday that China is against the spread of weapons of mass destruction and carriers for such weapons. He said China has strict rules against the spread of such weapons.

U.S. State Department spokesman Mark Toner said Thursday that Washington is not aware of any evidence that China violated the U.N. arms embargo.

Arms transfer expert Pieter Wezeman of the Stockholm International Peace Research Institute told the Associated Press that it would be difficult to prove whether Beijing violated U.N. sanctions because the vehicle could have been imported to North Korea from a third country, or it might have been meant for civilian purposes.

Michael Green of the Washington-based Center for Strategic and International Studies said at a U.S. congressional hearing Wednesday that China is not properly implementing the Security Council sanctions. He said he has seen evidence of North Korean companies on the sanctions list operating openly in China. And he said the Security Council sanctions committee has been ineffective.

"The sanctions committee of the Security Council has not done anything since it was originally charged to look at this in 2009," said Green.

When questioned by VOA Thursday, the head of the North Korea sanctions committee, Portuguese Ambassador José Filipe Moraes Cabral, said the sanctions committee has not yet discussed the alleged Chinese violation. He said the committee's experts are "doing their work" and a report is due in May.